Distance measuring devices in the form of hand-held measuring devices or industrial sensors have long been known and are commercially available. Their distance measuring range is up to 200 m and they are used, for example, in construction surveying, for example for the 3-dimensional surveying of rooms. For this purpose, a transmitter emits intensity-modulated radiation, in general wavelengths in the visible range being used, which facilitates the sighting of the measuring points. The radiation is reflected or scattered by the measured object and picked up by the receiver. The distance to the measured object is obtained on the basis of the phase position of the modulated radiation relative to the transmitter.
Such a measuring device is disclosed, for example, in EP 0 701 702. In this device, a semiconductor laser emits light to an object to be surveyed, this light being received again and evaluated after reflection. The measuring receiver has an optical system whose beam axis is oriented substantially parallel to the transmission axis, deflection elements for beam guidance or movable, trackable entry surface for the measuring radiation being used in the close vicinity.
In order to realise a highly precise measurement with a low level of extraneous light components, the received radiation must be limited to the measuring radiation component. This can be achieved by a suitable choice of the diameter of the detector surface of the receiver relative to the focal distance of the optical system. An advantageous lower ratio of diameter to focal distance in this context makes the arrangement sensitive with regard to the exact orientation and requires adjustment of the components, for example during manufacture, as can be realised by moveable adjusting elements or corresponding adjusting facilities.
An adjustable arrangement of transmitter and receiver is disclosed in EP 1 351 070, in which an electrooptical distance measuring system for large measuring ranges comprising the optical transmission axis and receiving axis arranged in parallel a distance apart is described. The radiation source and a small-area photodiode are mechanically connected rigidly to one another via an essentially rigidly connected circuit board assembly. The small-area photodiode is electrically conductive and is fixed in position by means of its electrical contacts on the circuit board assembly so as to be temporarily adjustable. The adjustment is therefore effected by a movement of the photodiode relative to the circuit board assembly, the photodiode being fixed after reaching the optimum position. By means of this fixing step to be carried out in the device, in which an individual electronic component must be moved, manufacture is made more complicated. In particular, the photodiode cannot already be mechanically fixed rigidly on the circuit board. This prevents utilisation of the advantages of surface-mounted devices which are soldered fully automatically by standard machines directly onto the conductor tracks, for example from points of view of assembly and strength.